Herbicide, harvesters may be part of 2018 curlyleaf plan
Fall has barely begun and the Lakes Area community is already preparing for next year's battle against the invasive curlyleaf pondweed. The weed caused navigational issues on the lake this past season as it clogged boat motors and jammed dock lifts. The Iowa Department of Natural Resources, local government entities, area protective agency representatives and the general public met Thursday to discuss a possible plan of action for next year. A mechanical harvester will likely be part of the plan again this year, with the possible addition of aquatic herbicides in certain areas.
DNR Fisheries Biologist Mike Hawkins said the DNR provided the working group of county and city entities with several approaches to weed management, based on the science of the curly leaf. He said the group put together Thursday's recommended plan based on the data provided. The group plans to meet again this week to discuss public feedback from the meeting and adjust the plan if necessary. Hawkins said the group came at the issue from all sides and there is no single, easy solution to the problem.
The current plan is to continue using the mechanical harvesting method, but it is only one tool in the proverbial tool belt, according to Hawkins.
"We're going to try and at least double the number of acres we mechanically harvested," Hawkins said.
He said the harvesting would largely be done on East Lake Okoboji. He said residents of the Carter Lake area have offered to loan another harvester to the group for use this spring, alongside the harvester purchased by Underwater Solutions last year. Hawkins said mechanically harvesting has the added benefit of removing the plant material — and the phosphorus it contains — from the water.
The other option being considered is the application of an aquatic herbicide.
Hawkins estimated the cost of mechanically harvesting curlyleaf is $750-$800 per acre, while herbicide would be more economical at $300-$350 per acre. The working group plans to use an integrated management approach, according to Hawkins. This approach would emphasize prevention and mechanical removal over herbicides.
Potential herbicide application caused apprehension among the Lakes Area public in 2016. Hawkins said the DNR director at the time called for the permitting process to be slowed and the situation reevaluated. He said the decision was generally good and provided time to learn more about the process.
"A lot of the entities that were concerned are part of the working group (now)," Hawkins said.
The working group is considering herbicide application on 10 acres of Lower Gar Lake and 10 acres in the far northern portion of East Lake Okoboji. Water samples will be taken to be sure the herbicide — called endothall or Aquathol K — does not move beyond the test sites. The herbicide must be applied at least 600 feet from potable drinking water intakes. Hawkins said the locations being considered are approximately 7 miles from the intakes. Hawkins also said the herbicide has no restriction on swimming or fishing after application.
"Even though this product is labeled for use on drinking water lakes, we want to be extra cautious," Hawkins said.
Attendees Thursday were also cautious and noted, while Aquathol K has been used on many lakes in Iowa, it has never been used on a lake used for drinking water.
“Both West Okoboji and Big Spirit are Class C lakes, which means they are designated as drinking water sources for human consumption,” Hawkins said. “Although Aquathol K is approved by the EPA for use on these Class C lakes within 600 feet of an intake, we have no plans of doing so in West Okoboji. Neither East Okoboji or Lower Gar are Class C waters, and the test areas we have chosen are several miles from the closest water source, West Okoboji.”
Personnel at the Iowa Lakeside Lab will be monitoring the test areas to see how Aquathol K moves from the treatment area and how curlyleaf and other native plants respond.
Hawkins said the herbicide is commonly used in the United States and highlighted a study by Cornell University, which examined a similar application of endothall in Monroe County, New York, in 2011. The study said, “Endothall is poorly absorbed through skin and the small amounts that might be ingested while swimming are not considered toxic or harmful.” The study also said the level of endothall found to be toxic to waterfowl and wildlife well surpasses the EPA-approved concentration for application.
The university developed a fact-sheet regarding the chemical and Hawkins said he hopes to work with the Iowa State University Extension and Outreach to develop a similar fact-sheet for local use.
Hawkins stressed the importance of providing clear and accurate data for the public to consider. Without it, some local residents have reportedly taken to applying household herbicides from the end of their docks. Adding to the issue, Hawkins said what some think to be curlyleaf is actually misidentified native vegetation. In reality, the weed's lifecycle ends in late summer.
“Even when you pick up a can of Raid or Round Up, there's a label on it and that's the law you have to follow for use,” Hawkins said. “When you don't follow that EPA label, you're actually breaking federal law.”
State laws also reflect the federal restrictions on applying herbicides to public waters, according to Hawkins. He said the DNR is the only entity permitted to apply herbicides to the Iowa Great Lakes. In addition, conservation officers have the power to file citations for unapproved application, with sufficient evidence.
Hawkins said he has sensed the public's vilification of aquatic plants since curlyleaf became an issue again in recent years.
“Our native plant community is really important and even curlyleaf can have some benefits,” Hawkins said. “We are experiencing the best water quality we have in a long time.”
The biologist said vegetation provides habitat for fish and invertebrates and adds to water clarity by dampening wave action and absorbing nutrients. Hawkins indicated the public's misguided attempts to kill aquatic plants would do more damage than good.
“To get rid of all these plants means we go back to bluegreen algae,” Hawkins said. “Those nutrients have to go somewhere.”
Mary Skopec, director of Lakeside Laboratory, told Thursday's crowd the algae can be dangerous.
“A blue-green algae bloom can be very toxic to both humans and pets,” she said. “When in doubt, stay out.”
Concerned with more than the illegal nature of applying herbicides off docks, East Okoboji Lakes Improvement Corporation President Bill Maas said the behavior may cause a life-or-death situation.
“It really scares the heck out of me,” Maas said. “Those are chemicals that are not really aqua-related. You look at the label and those are really harmful to young children.”
Mass noted the majority of swimmers are young children who would undoubtably ingest or absorb the chemical if a neighbor applied it illegally. Yet, he said there seems to be a fear among the public to report illegal activity next door.
“People will get upset about other things but this could potentially kill someone and people don't talk about it,” Maas said.
Hawkins said the public can report such activity to the DNR and remain anonymous. Maas said he would like to create a local tip line to speed the state's response.
Overall, the proposed plan would cost approximately $40,000 to execute. Maas said the project will be partially funded by a grant from the DNR, through the Marine Fuel Tax Fund. The EOLIC plans to back the city of Orleans, of which Maas is the mayor, with $10,000 to use toward the required 25 percent match for the grant funding. The city was similarly backed by the EOLIC last year in order to secure the harvester. Maas said other cities, such as Spirit Lake, had expressed their willingness to back the project. While he appreciated their willingness, Maas said the process seemed easiest if it were to go through Orleans again, knowing the council had been fully supportive in the past.
“We're glad to do the service and help people out,” Maas said.
Maas said the EOLIC has some funds in reserve that could be used for the project's total cost and the DNR grant would reimburse Orleans after the fact. However, he said the EOLIC would prefer to do some fundraising and not to dip into the reserve funding too deeply, if possible. EOLIC representatives have received several pledges and plan to seek more from local marinas and businesses. Maas envisions establishing a “war chest” of water protection funds to pay for such large-scale expenses.
However, he pointed out fundraising is a bit tricky in this instance, because a large number of lake users are not from the area, emphasizing the state-wide nature of the issue.
“The water does belong to the state of Iowa, which is all of us, but I can't see asking a little old lady in Davenport to put in a dollar,” Maas said.
The Orleans mayor said he was unsure whether the EOLIC would be partnering with other protective associations, like the Okoboji Protective Association, because the current plan does not largely impact their respective waters. He said, if the plan develops more and moves into other portions in the chain of lakes, it might merit a more serious look at partnering with other associations.